The present invention relates to a process and apparatus for the production of compounds from a gas or a gas mixture by the plasma method. The invention is particularly useful for reacting atmospheric nitrogen and oxygen to form nitric oxides, as a step in producing synthetic nitrogenous fertilizer, and the invention is therefore described below with respect to such an application.
The most economical and popular method today for fixing nitrogenous fertilizer is the Haber-Bosch process in which hydrogen is bonded with nitrogen under high pressure, and in the presence of catalyst, to form ammonia. However, this process requires vast quantities of fossil fuel, such as oil and natural gas, to provide the hydrogen. With the rapidly increasing cost and rapidly depleting supplies of fossil fuel, it is becoming increasingly important to find an alternative economical process for producing synthetic nitrogenous compounds.
Another method, known even before the Haber-Bosch process, is based on the plasma or arc-discharge technique and uses atmospheric nitrogen and oxygen to form nitric oxide. One technique for implementing this process is based on the Birkeland and Eyde furnace, which produces a fan-shaped arc stabilized by a constant magnetic field. Another technique is based on the Schonherr furnace, which stabilizes the arc by air turbulence, the air entering at the bottom through tangential openings and given a rapid spiral motion inside the arc zone. However, both furnaces require such large amounts of electrical power that they both became economically unfeasible and were replaced by the presently-used Haber-Bosch process.